Mitral valve repair is the procedure of choice to correct mitral regurgitation of all etiologies. With the use of current surgical techniques, between 70% and 95% of regurgitant mitral valves can be repaired. The advantages of mitral valve repair over mitral valve replacement are well documented. These include better preservation of cardiac function and reduced risk of anticoagulant-related hemorrhage, thromboembolism and endocarditis.
In current practice, mitral valve surgery requires an extremely invasive approach that includes a chest wall incision, cardiopulmonary bypass, cardiac and pulmonary arrest, and an incision on the heart itself to gain access to the mitral valve. Such a procedure is associated with high morbidity and mortality. Due to the risk associated with this procedure, many of the sickest patients are denied the potential benefits of surgical correction of mitral regurgitation. In addition, patients with moderate, symptomatic mitral regurgitation are denied early intervention and undergo surgical correction only after the development of cardiac dysfunction.
Mitral regurgitation is a common occurrence in patients with heart failure and a source of important morbidity and mortality in these patients. Mitral regurgitation in patients with heart failure is caused by changes in the geometric configurations of the left ventricle, papillary muscles and mitral annulus. These geometric alterations result in mitral leaflet tethering and incomplete coaptation at systole. In this situation, mitral regurgitation is corrected by plicating the mitral valve annulus, either by (i) sutures alone or by (ii) sutures in combination with a support ring, so as to reduce the circumference of the distended annulus and restore the original geometry of the mitral valve annulus.
More particularly, current surgical practice for mitral valve repair generally requires that the posterior mitral valve annulus be reduced in radius by surgically opening the left atrium and then fixing sutures, or more commonly sutures in combination with a support ring, to the internal surface of the annulus; this structure is used to cinch the annulus, in a pursestring-like fashion, to a smaller radius, thereby reducing mitral regurgitation by improving leaflet coaptation.
This method of mitral valve repair, generally termed xe2x80x9cannuloplastyxe2x80x9d, effectively reduces mitral regurgitation in heart failure patients. This, in turn, reduces symptoms of heart failure, improves quality of life and increases longevity. Unfortunately, however, the invasive nature of mitral valve surgery and the attendant risks render most heart failure patients poor surgical candidates. Thus, a less invasive means to increase leaflet coaptation and thereby reduce mitral regurgitation in heart failure patients would make this therapy available to a much greater percentage of patients.
Mitral regurgitation also occurs in approximately 20% of patients suffering acute myocardial infarction. In addition, mitral regurgitation is the primary cause of cardiogenic shock in approximately 10% of patients who develop severe hemodynamic instability in the setting of acute myocardial infarction. Patients with mitral regurgitation and cardiogenic shock have about a 50% hospital mortality. Elimination of mitral regurgitation in these patients would be of significant benefit. Unfortunately, however, patients with acute mitral regurgitation complicating acute myocardial infarction are particularly high-risk surgical candidates, and are therefore not good candidates for a traditional annuloplasty procedure. Thus, a minimally invasive means to effect a temporary reduction or elimination of mitral regurgitation in these critically ill patients would afford them the time to recover from the myocardial infarction or other acute life-threatening events and make them better candidates for medical, interventional or surgical therapy.
As a result, one object of the present invention is to provide an apparatus and method for treating mitral regurgitation which does not suffer from the disadvantages associated with conventional annuloplasty.
Another object of the present invention is to provide an apparatus and method for treating mitral regurgitation which can be deployed either permanently (e.g., for patients suffering from heart failure) or temporarily (e.g., for patients suffering from mitral regurgitation with acute myocardial infarction).
These and other objects are addressed by the present invention, which is made possible by the discovery that the mitral annulus may be remodeled without the plication of conventional, open-surgery annuloplasty.
With the above and other objects in view, a feature of the invention is the provision of an apparatus for reducing mitral regurgitation. The apparatus comprises a bendable elongated body adapted to be inserted into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the elongated body being adjustable between a first configuration adapted to be delivered into the coronary sinus and a second configuration adapted to exert a force onto the posterior annulus. The body comprises a flexible spine having a proximal end and a distal end, and a flexible wire mounted on the spine and having a distal end fixed to the spine proximate to the distal end of the spine, and having a proximal portion extending from the proximal end of the spine. Axial movement of the wire causes a change in the spine from the first configuration to the second configuration to exert the force on the posterior annulus and thereby reduce mitral regurgitation.
In accordance with a further feature of the invention, there is provided a further apparatus for reducing mitral regurgitation. The apparatus comprises a bendable elongated body adapted to be inserted into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the elongated body being adjustable between a first configuration adapted to be delivered into the coronary sinus and a second configuration adapted to exert a force onto the posterior annulus. The body comprises a flexible spine having a proximal end and a distal end, and a flexible wire mounted on the spine and having a distal end fixed to the spine proximate to the distal end of the spine, and having a proximal portion extending from the proximal end of the spine. Pulling of the wire causes straightening of the spine to move the spine from the first configuration to the second configuration to exert the force on the posterior annulus and thereby reduce mitral regurgitation.
In accordance with a further feature of the invention, there is provided a method for reducing mitral regurgitation. The method comprises the steps of positioning a prosthesis in a coronary sinus, the prosthesis comprising a bendable elongated body adapted to be inserted into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the elongated body being adjustable between a first configuration adapted to be delivered into the coronary sinus and a second configuration adapted to exert a force onto the posterior annulus, the body comprising a flexible spine having a proximal end and a distal end, and a flexible wire mounted on the spine and having a distal end fixed to the spine proximate to the distal end of the spine, and having a proximal portion extending from the proximal end of the spine; and moving the wire axially to cause a change in the spine from the first configuration to the second configuration to exert the force on the posterior annulus and thereby reduce mitral regurgitation.
In accordance with a further feature of the invention, there is provided a further method for reducing mitral regurgitation, the method comprising the steps of positioning a prosthesis in a coronary sinus, the prosthesis comprising a bendable elongated body adapted to be inserted into the coronary sinus of a patient in the vicinity of the posterior leaflet of the mitral valve, the elongated body being adjustable between a first configuration adapted to be delivered into the coronary sinus and a second configuration adapted to exert a force onto the posterior annulus, the body comprising a flexible spine having a proximal end and a distal end, and a flexible wire mounted on the spine and having a distal end fixed to the spine proximate to the distal end of the spine, and having a proximal portion extending from the proximal end of the spine; and pulling the wire to straighten the spine and to move the spine from the first configuration to the second configuration to exert the force on the posterior annulus and thereby reduce mitral regurgitation.
In accordance with still further feature of the invention, there is provided a method for reducing mitral regurgitation, the method comprising scarring the mitral valve annulus to cause contraction thereof.
The above and other features of the invention, including various novel details of construction and combinations of parts and method steps, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular devices and methods embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.